MAGETWO-51858: Convert literal class names to \Namespace\Classname::class

Author: Stanislav Idolov

lib/internal/Magento/Framework/ObjectManager/Test/Unit/Config/Mapper/_files/mapped_simple_di_config.php

@@ -30,7 +30,7 @@
     ],
     'customCacheInstance' => [
         'shared' => true,
-        'type' => 'Magento\Framework\App\Cache',
+        'type' => \Magento\Framework\App\Cache::class,
         'arguments' => [],
     ],
     'customOverriddenInstance' => [